Parse perfcheck results

refactoring arguments
process csv file only if newer commits
add columned output
calculate deltas & alert messages

Change-Id: Ib7ba87e9cb55b03ac8665db7a8dc302d2e8611a0
Reviewed-on: https://gerrit.libreoffice.org/12155
Reviewed-by: Matúš Kukan <matus.kukan@collabora.com>
Tested-by: Matúš Kukan <matus.kukan@collabora.com>